English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We compare numerical evolutions performed with the BSSNOK formulation and aconformal decomposition of a Z4-like formulation of General Relativity. Theimportant difference between the two formulations is that the Z4 formulationhas a propagating Hamiltonian constraint, whereas BSSNOK has a zero-speedcharacteristic variable in the constraint subsystem. In spherical symmetry weevolve both puncture and neutron star initial data. We demonstrate that thepropagating nature of the Z4 constraints leads to results that comparefavorably with BSSNOK evolutions, especially when matter is present in thespacetime. From the point of view of implementation the new system is a simplemodification of BSSNOK.

Constraint violation in free evolution schemes: comparing BSSNOK with a conformal decomposition of Z4